facebook or google plus
 

which is the best?

Both are very popular Sites. so use both site.

I prefer both the sites for ranking my website.

They are both good for SEO but I rather FB

My vote is for facebook

I like G+ because it of Google

Depends on your audience really... There's a lot of anecdotal 'evidence' showing a good following on Google+ helps your SEO efforts quite a bit so yeah they're both important but if you want to emphasize one over the other then find out where your audience actually hang out.